New NUMA support coming to CURRENT
jroberson at jroberson.net
Tue Jan 9 19:51:00 UTC 2018
I am working on merging improved NUMA support with policy implemented by
cpuset(2) over the next week. This work has been supported by Dell/EMC's
Isilon product division and Netflix. You can see some discussion of these
The work has been done in user/jeff/numa if you want to look at svn
history or experiment with the branch. It has been tested by Peter Holm
on i386 and amd64 and it has been verified to work on arm at various
We are working towards compatibility with libnuma and linux mbind. These
commits will bring in improved support for NUMA in the kernel. There are
new domain specific allocation functions available to kernel for UMA,
malloc, kmem_, and vm_page*. busdmamem consumers will automatically be
placed in the correct domain, bringing automatic improvements to some
cpuset will be able to constrains processes, groups of processes, jails,
etc. to subsets of the system memory domains, just as it can with sets of
cpus. It can set default policy for any of the above. Threads can use
cpusets to set policy that specifies a subset of their visible domains.
Available policies are first-touch (local in linux terms), round-robin
(similar to linux interleave), and preferred. For now, the default is
round-robin. You can achieve a fixed domain policy by using round-robin
with a bitmask of a single domain. As the scheduler and VM become more
sophisticated we may switch the default to first-touch as linux does.
Currently these features are enabled with VM_NUMA_ALLOC and MAXMEMDOM. It
will eventually be NUMA/MAXMEMDOM to match SMP/MAXCPU. The current NUMA
syscalls and VM_NUMA_ALLOC code was 'experimental' and will be deprecated.
numactl will continue to be supported although cpuset should be preferred
going forward as it supports the full feature set of the new API.
Thank you for your patience as I deal with the inevitable fallout of such
sweeping changes. If you do have bugs, please file them in bugzilla, or
reach out to me directly. I don't always have time to catch up on all of
my mailing list mail and regretfully things slip through the cracks when
they are not addressed directly to me.
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